Hello I have this error Deprecated: Creation of dynamic property Joomla\CMS\Application\SiteApplication::$cck_jquery_more is deprecated in C:\laragon-6.0.0\www\joomla5\libraries\cck\_\cck.php on line 578.
Yes SEBLOD 4 is compatible with Joomla! 5. You may find some notices/warnings or UI styling issue, but you can upgrade, and if you see something broken (a regression), feel free to report on Github.